1. Field of the Invention
The present invention relates to the information processing apparatus and its heat spreading method, particularly relating to a mobile information processing apparatus that can readily release a heat generated to outside.
2. Background Arts
Conventionally, a technique relating to this field is disclosed in Japanese unexamined patent publication HEI 9-6481. The conventional mobile information processing apparatus mentioned in this publication as illustrated in FIG. 47 comprises a lid 51 incorporating a heat pipe 3 and a heat spreading board 5, and a main body 50 incorporating a heat generation unit 1. The heat generated from the heat generation unit 1 is released from the heat spreading board 5 via a thermally conductive block 2.
Another conventional techniques relating to this field are Japanese unexamined patent publications HEI 8-87354, HEI 8-204373 and HEI 8-261672.
FIG. 48 illustrates a side view of disintegrated lid 51. Following components are installed in between a front panel 60 and an external chassis 12: a liquid crystal display panel 7; a back light 10; a back light optical system 62; and a inverter circuit board 95 for the back light.
FIG. 49 illustrates a temperature profile of the lid 51 and the main body 50. Curved lines in the temperature profile illustrate isotherms. As can be seen from FIG. 49, a lot of heat is being generated from the CPU 1, the back light 10 and the inverter circuit board 95.
The conventional mobile information processing apparatus has difficulty in conducting heat, which is sent from the heat pipe 3, throughout the heat spreading board due to an inadequate heat conduction to a direction of plane of the heat spreading board 5. As a result of this, from within various positions of the heat spreading board 5, only positions that are close to the heat pipe 3 were able to contribute in spreading the heat such that an effect of heat spreading in the conventional mobile information processing apparatus is therefore inadequate.
Also, the conventional mobile information processing apparatus has problems of noise and loss of energy, which are caused by a leakage current from the back light inverter circuit board 95 incorporated at an inner side of the lid 51, flowing into the metallic chassis 12, as shown in FIG. 21.